THE INTERNAL STRUCTURE OF VEGETATED COASTAL SAND DUNES, SABLE-ISLAND, NOVA-SCOTIA

New data and a comprehensive analysis of stratification and sedimentation in the complex vegetated dunes of Sable Island, Nova Scotia are presented. The internal structures of the dunes are analyzed using a descriptive legend, from an earlier paper (Byrne and McCann, 1990), which was based on three elements-grain size, stratification, and the nature of plant remains. Analysis of the stratification and sedimentary character of the dunes at three sites along the north shore and at ten sites in the interior of the Island involved modifications to the original descriptive legend and a more comprehensive listing of the modes of deposition. The sites discussed here represent the evidence that was available during the field season (summer 1987 and 1988) without extensive excavations and disturbance of the terrain. Genetic interpretation of the complete data set indicates that the main dunes of Sable Island fall into two categories: (1) Primary dunes, which have developed in situ, through several phases of sedimentation at the back of the north beach (three sites). (2) Secondary dunes, including various remnant forms, which result from the passage of migrational dunes, in the interior of the island (ten sites). Three types of secondary dunes are defined. These dune types are summarized in a map and as a block diagram that can be used to document the development of the dunes and dune systems on the island.